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Temperature and Stress Evaluation during Three Different Phases of Friction Stir Welding of AA 7075-T651 Alloy
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The current study performs an explicit nonlinear finite element simulation to predict temperature distribution and consequent stresses during the friction stir welding (FSW) of AA 7075-T651 alloy. The ABAQUS® finite element software was used to model and analyze the process steps that involve plunging, dwelling, and traverse stages. Techniques such as Arbitrary Lagrangian–Eulerian (ALE) formulation, adaptive meshing, and computational feature of mass scaling were utilized to simulate sequence events during the friction stir welding process. The contact between the welding tool and workpiece was modelled through applying Coulomb’s friction model with a nonlinear friction coefficient value. Also, the model considered the effect of nonlinear material properties as well as heat transfer conditions such as heat losses due to convection and thermal contact conductance between the workpiece and the backing plate interface on the thermal history. To validate the computational model results, an experimental procedure was carried out to measure temperature history on both sides of the specimen as well as the plunging force throughout the whole process time. The results obtained showed that symmetrical temperature distribution throughout the workpiece width was distinguished, implying that the tool rotation has a minor effect on the final temperature distribution. In addition, asymptotic V shape with high gradient temperature value in the weld nugget region after the full plunging was distinguished. Mechanical stresses and related plastic deformations generated, while achieving the FSW samples were evaluated in addition to the tool reaction force and heat generated to protect against tool failure.

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Publication Date
Sun Feb 04 2018
Journal Name
Journal Of The College Of Education For Women
Phrenic nerve paralysis during cryoballoon ablation for atrial fibrillation: A comparison between the first- and second-generation balloon
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The present study deals with the effect of teaching speaking Strategies (SS) on EFL Iraqi College students. The use of speaking strategies not only solves learners’ communication problems, but also enhances the learner’s interaction in target language, and improves their oral proficiency .The aim of the study is to find out the effect of teaching SS used by EFL College students .The learner of the first stage is population of the study at the Department of English, College of Education /Ibn-Rushd .The sample consists of (60) students distributed on experimental group(A) as well as control group(B) each group contains (30) students . In order to achieve the aim of the study, questionnaire has been constructed to be taught on the experime

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Publication Date
Tue Sep 15 2020
Journal Name
Journal Of Baghdad College Of Dentistry
The impact of various staining substances and immersion time on the stainability of bonded sapphire brackets with three kinds of light cure orthodontic adhesives (An in-vitro study)
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Background: The need of the patient for a more reasonable esthetic orthodontic intervention has risen nowadays. Thus, orthodontists make use of esthetic orthodontic materials like brackets, ligature elastics, and arch wires. The esthetic brackets come as different forms of materials, such as ceramic brackets, which have their stainability remaining as the most important consideration for the patients and the orthodontists. This study aimed to compare the staining effects of various staining materials, including black tea, cigarette smoke and Pepsi, as well as the time effect on the color stability of sapphire ceramic brackets bonded with three kinds of light cure orthodontic adhesives: Transbond, Resilience and Enlight. Materials and Met

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Publication Date
Sun Jun 26 2022
Journal Name
Electrical Engineering
Optimal insulation design of form-wound stator winding with stress grading system under fast rise-time excitation
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The effective insulation design of the stress grading (SG) system in form-wound stator coils is essential for preventing partial discharges and excessive heat generation under pulse-width modulation excitation. This paper proposes a method to find the optimal insulation design of the SG system aimed at reducing the dielectric and thermal stresses in the machine coil. The non-uniform transmission line model is used to predict the voltage propagation along the overhang, SG, and slot regions considering the variation in the physical properties of the insulation layers. The machine coil parameters for different insulation materials are calculated by using the finite element method. Two optimization algorithms, fmincon and particle swarm optimiz

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Publication Date
Wed Jan 10 2018
Journal Name
Al–bahith Al–a'alami
Work Stress Sources of the Communicator in Public Relations “A field study on Governmental Institutions in UAE”.
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This study addressed the work stress sources and level of the communicator in public relations in governmental institutions in the United Arab Emirates. The importance of this study is the lack of studies on work stress of the communicator in public relations. The study aimed to investigate the work stress source Physical, individual, groups, organizational and Professional source which effect on the performance of communicator in public relations. The researcher used the descriptive approach and questionnaire as an essential tool for collecting information. Some of the important results of the study are The communicator in public relations facing stress in work by 42% which affect on his performance by average level. The organizational

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Publication Date
Mon Feb 21 2022
Journal Name
Applied Sciences
The Behavior of Hybrid Fiber-Reinforced Concrete Elements: A New Stress-Strain Model Using an Evolutionary Approach
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Several stress-strain models were used to predict the strengths of steel fiber reinforced concrete, which are distinctive of the material. However, insufficient research has been done on the influence of hybrid fiber combinations (comprising two or more distinct fibers) on the characteristics of concrete. For this reason, the researchers conducted an experimental program to determine the stress-strain relationship of 30 concrete samples reinforced with two distinct fibers (a hybrid of polyvinyl alcohol and steel fibers), with compressive strengths ranging from 40 to 120 MPa. A total of 80% of the experimental results were used to develop a new empirical stress-strain model, which was accomplished through the application of the parti

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Publication Date
Sat Mar 30 2019
Journal Name
Advances In Bioresearch
Survey of Species Insects Indoor in Different Localities of Iraq
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Publication Date
Mon Oct 01 2018
Journal Name
International Journal Of Civil Engineering And Technology
Properties of reactive powder concrete with different types of cement
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Publication Date
Mon Oct 01 2018
Journal Name
International Journal Of Civil Engineering And Technology
Properties of reactive powder concrete with different types of cement
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Concrete is widely used in construction materials since early 1800's. It has been known that concrete is weak in tension, so it requires some addition materials to have ductile behavior and enhance its tensile strength and strain capacity to improve their uses. In this study reactive powder concrete (RPC) was used with steel fiber by using different types of cement; (Ordinary Portland cement (OPC) and/or Portland- Limestone cement (PLC)) with three types of mixtures (OPC at the first mix, 50 % OPC and 50 % PLC at the second mix and PLC at the third mix). The behavior of RPC with steel fibers on compressive strength and tensile strength of concrete with different ages of curing (7, 14, 28 and 60) days and shrinkage have been studied. The clo

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Publication Date
Mon Oct 05 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Assessment of cortisol as salivary psychological stress marker in relation to temporomandibular disorders among a sample of dental students
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Background: University dental students perceived a higher level of stress prior to the final exam associated with raised salivary cortisol levels which could be considered as a useful noninvasive biomarker for measuring acute stress. Using a Helkimo anamnestic and clinical dysfunction scoring for temporomandibular disorders can give a better insight about the association of this marker and temporomandibular joint disorders. The aim of this study was to evaluation level of salivary cortisol in stressor students with temporomandibular disorder and the relation between this marker in relation to temporomandibular disorder severity. This might give a better understanding to the role of psychological stress as an etiological factor for developin

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Publication Date
Mon Oct 07 2024
Journal Name
F1000research
Oral pre-treatment with Citronellol ameliorates Methotrexate-induced nephrotoxicity in Wistar rats via targeting oxidative stress and inflammation
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Background Methotrexate (MTX) is a classical folic acid antagonist widely used in the treatment of malignant and non-malignant disorders. However, its clinical application is often restricted by concomitant adverse effects, including renal damage. Numerous studies have highlighted the role of oxidative stress and inflammation in mediating MTX-related nephrotoxicity. Therefore, the current study aimed to explore the possible renoprotective action of Citronellol (CT), a natural compound with prominent antioxidant and anti-inflammatory activities, against nephrotoxicity induced by MTX. Methods To fulfill our objective, 24 adult male Wistar rats were randomly allocated into four groups: control, MTX, 100 mg/kg CT plus MTX and 200 mg/kg C

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